My DS is 7 and very big for his age, and his dx is ASD. He's very young for his age in most ways and still likes very 'young' things. I sometimes find it hard to find toys the right size/suitable that he will actually play with (I find this with clothing too but that's a whole other issue!). An example is he LOVES those little tikes cars but they are way way too small for him, I've told him not to try to get in them again as last time he got stuck!!
I've been trying to remedy this a little by adding a few toys and thought we could share ideas on what toys our dcs have enjoyed. 
I found
- a little tikes 'giant' slide - it is tall/long enough, but very sturdy and robust, DS loves it.
- trusty trampoline (we've had this a while)
- a large garden connect four. This has actually got DS taking turns at a game with me and thinking through his moves in the game. He also likes playing with the large circular counters too.
I've applied to cerebra for a grant for some sensory equipment so I've got my fingers crossed for that. I've requested help with getting a dark den, a pack of light up toys (dark den accessory kit) and a chimeabout. DS plays with these at groups and loves them.